Phosphatidylserine (PS) is important for maintaining growth, cytoskeleton, and various functions in yeast; however, its role in stress responses is poorly understood. In Schizosaccharomyces pombe, the PS synthase deletion (pps1∆) mutant shows defects in growth, morphology, cytokinesis, actin cytoskeleton, and cell wall integrity, and these phenotypes are rescued by ethanolamine supplementation. Here, we evaluated the role of Pps1 in the salt stress response in S. pombe. We found that pps1∆ cells are sensitive to salt stresses such as KCl and CaCl₂ even in the presence of ethanolamine. Loss of the functional cAMP-dependent protein kinase (git3∆ or pka1∆) or phospholipase B Plb1 (plb1∆) enhanced the salt stress-sensitive phenotype in pps1∆ cells. Green fluorescent protein (GFP)-Pps1 was localized at the plasma membrane and endoplasmic reticulum regardless of the stress conditions. In pka1∆ cells, GFP-Pps1 was accumulated around the nucleus under the KCl stress. Pka1 was localized in the nucleus and the cytoplasm under normal conditions and transferred from the nucleus to the cytoplasm under salt-stress conditions. Pka1 translocated from the nucleus to the cytoplasm during CaCl₂ stress in the wild-type cells, while it remained localized in the nucleus in pps1∆ cells. Expression and phosphorylation of Pka1-GFP were not changed in pps1∆ cells. Our results demonstrate that Pps1 plays an important role in the salt stress response in S. pombe.

磷脂酰丝氨酸 (PS) 对于维持酵母的生长、细胞骨架和各种功能非常重要；然而，人们对它在应激反应中的作用知之甚少。在粟酒裂殖酵母中，PS 合酶缺失 ( pps1Δ ) 突变体在生长、形态、胞质分裂、肌动蛋白细胞骨架和细胞壁完整性方面表现出缺陷，这些表型可以通过补充乙醇胺来挽救。在这里，我们评估了 Pps1 在粟酒裂殖酵母盐胁迫反应中的作用。我们发现，即使在乙醇胺存在的情况下，pps1Δ细胞对KCl和CaCl ₂等盐胁迫也很敏感。功能性 cAMP 依赖性蛋白激酶（git3Δ或pka1Δ）或磷脂酶 B Plb1 ( plb1Δ ) 的丧失增强了pps1Δ细胞中盐胁迫敏感的表型。无论应激条件如何，绿色荧光蛋白 (GFP)-Pps1 都定位于质膜和内质网。在pka1Δ细胞中，在 KCl 胁迫下，GFP-Pps1 在细胞核周围聚集。 Pka1在正常条件下定位于细胞核和细胞质，在盐胁迫条件下从细胞核转移到细胞质。在野生型细胞中， CaCl ₂应激期间，Pka1 从细胞核转移到细胞质，而在pps1Δ细胞中，它仍然定位在细胞核中。 Pka1-GFP 的表达和磷酸化在pps1Δ细胞中没有改变。我们的结果表明 Pps1 在粟酒裂殖酵母的盐胁迫反应中发挥着重要作用。